Extended Ischemic Times During Ex Vivo Lung Perfusion Do Not Lead to Worse Outcomes

E. Y. Cui¹, D. A.. Gouchoe¹, D. Satija², A. Aly², M. C. Henn², K. Choi², D. Nunley², N. A. Mokadam², A. M. Ganapathi³, B. A. Whitson^2
1COPPER Lab, The Ohio State University Wexner Medical Center, Columbus, Ohio ²The Ohio State University Wexner Medical Center, Columbus, Ohio ³The Ohio State University, Columbus, Ohio

Purpose: Increasing ischemic times have been associated with worse outcomes in lung transplantation, however this relationship has not been well described in recipients who receive lungs evaluated by ex vivo lung perfusion (EVLP). We sought to identify the association of increasing ischemic times and their effect on outcomes following lung transplantation.

Methods: Adult, primary lung transplants from 2/28/18-10/20/22 were identified from the United Network for Organ Sharing (UNOS) Database. Recipients younger than 18, multi-organ recipients, re-transplants or those who did not receive an allograft that was evaluated by EVLP were excluded. Recipients were then stratified into three groups based on total ischemic time (TOT): short TOT (sTOT, 0 to < 7 hours), medium TOT (mTOT, 7> to < 14 hours), and extended TOT (eTOT, +14 hours). The sTOT, mTOT and eTOT groups were assessed with comparative statistics and long-term survival was assessed by Kaplan-Meier methods. A Cox regression using select donor and recipient criteria was created to determine the association of ischemic time in EVLP donors and long-term mortality.

Results: There were 86 recipients identified in the sTOT group, 351 in the mTOT group and 193 in the eTOT group. Those in the sTOT were more likely to be perfused by the organ perfusion organization, while those in the mTOT group were more likely to be perfused by the transplant program and those in the eTOT group were mostly likely to be perfused by an external perfusion center (p < 0.0001). The eTOT had the longest distance traveled and highest incidence of donation after circulatory death (DCD) donors (p < 0.05). Those in the eTOT group had a trend towards higher incidence of severe primary graft dysfunction (PGD3), however this was not significant (p>0.05). Extra-corporeal membrane oxygenation (ECMO) use at 72 hours was significantly elevated in the eTOT group (p=0.027). There were no further significant differences in post-operative outcomes, nor recipient cause of death (Table). Kaplan-Meier methods revealed no significant difference in long-term survival between groups (p=0.97, Figure). On multivariable analysis, ischemic time was not associated with long-term mortality whereas recipient age, creatinine, lung allocation score and DCD status were associated (p < 0.05 for all).

Conclusion: Although exact EVLP perfusion techniques cannot be elucidated from this analysis, all groups had similar long-term survival and peri-operative outcomes. EVLP thus allows for the safe prolonged preservation of allografts, which will allow for longer distance retrievals and help overcome logistic issues that delay transplants. Based on these data, transplant providers should not be dissuaded from using an allograft with projected extended ischemic time if EVLP is available.

Identify the source of the funding for this research project: This project received Division funding. Additionally, BAW is supported through the National Institutes of Health National Heart Lung and Blood Institute grant R01HL143000.